Former Marshall Wace trader Scott Arnold has filed a claim against a London-based hedge fund for a share of the proceeds from his investment in stablecoin issuer Circle Internet Group Inc. Arnold says he was the one who brokered the deal. Marshall Wace has invested in Circle since 2021, putting in about $200 million and owning more than 8.50 million shares, or about 4 percent, before the company goes public on the New York Stock Exchange on June 5, making it one of the fund's most profitable ven...